Abstract

We demonstrate highly efficient inverted bottom-emission organic light-emitting diodes (IBOLEDs) by using cesium hydroxide (CsOH) doped tris-(8-hydroxyquinoline) aluminum as the electron injection layer on indium tin oxide cathode, which could significantly enhance the electron injection, resulting in a large increase in luminance and efficiency. The maximum luminance, current efficiency, and power efficiency reach , , and , respectively, which are 40%–50% higher in efficiency than that of IBOLEDs with cesium carbonate doped as the electron injection layer, where the efficiencies are only and . Our results indicate that CsOH doped should be an effective electron injection layer on a wide range of electrodes to fabricate high performance OLEDs.

Received 05 April 2008Accepted 14 June 2008Published online 03 July 2008

Acknowledgments:

We would like to thank the Foundation of Jilin Research Council (20050517), the Foundation of Changchun Research Council (2007GH06), the Science Fund for Creative Research Groups of NSFC (20621401), and the Ministry of Science and Technology of China (863 Program No. 2006AA03A161) for financial support.

Abstract

We demonstrate highly efficient inverted bottom-emission organic light-emitting diodes (IBOLEDs) by using cesium hydroxide (CsOH) doped tris-(8-hydroxyquinoline) aluminum as the electron injection layer on indium tin oxide cathode, which could significantly enhance the electron injection, resulting in a large increase in luminance and efficiency. The maximum luminance, current efficiency, and power efficiency reach , , and , respectively, which are 40%–50% higher in efficiency than that of IBOLEDs with cesium carbonate doped as the electron injection layer, where the efficiencies are only and . Our results indicate that CsOH doped should be an effective electron injection layer on a wide range of electrodes to fabricate high performance OLEDs.